<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>后盾人</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }

        body {
            width: 100vw;
            height: 100vh;
            background: #34495e;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .heart {
            width: 200px;
            height: 200px;
            background: #e74c3c;
            transform: rotate(45deg) scale(.5);
            animation-name: hd;
            animation-duration: 2s;
            opacity: .5;
            animation-iteration-count: infinite;
        }

        @keyframes hd {
            25% {
                opacity: 1;
                transform: rotate(45deg) scale(1);
            }

            50% {
                opacity: .5;
                transform: rotate(45deg) scale(.5);
            }

            75% {
                opacity: 1;
                transform: rotate(45deg) scale(1);
            }

            85% {
                opacity: .5;
                transform: rotate(45deg) scale(.5);
            }

            to {
                opacity: 1;
                transform: rotate(45deg) scale(1);
            }
        }

        .heart::before {
            content: '';
            width: 200px;
            height: 200px;
            border-radius: 50%;
            position: absolute;
            background: #e74c3c;
            transform: translateX(-100px);
        }

        .heart::after {
            content: '';
            width: 200px;
            height: 200px;
            border-radius: 50%;
            position: absolute;
            background: #e74c3c;
            transform: translateY(-100px);
        }
    </style>
</head>

<body>
    <div class="heart"></div>
</body>

</html>